Pete, deer rawhide is good backing material. Is it tanned, or still raw? If it's already been tanned, it probably won't work as well as just rawhide. I don't know about narrowing the limbs, rawhide is more of a protective backing than a working backing. Any kind of glue from hide glue to Titebond should work well, just dampen the hide and put it on, maybe wrap it with an Ace bandage or something for awhile. Any finish should work over it, Helmsman spar urethane has worked good for me on whitewood bows her in the Mountains of Moisture.